Improvement in boilers for steam fire-engines



lf. N. DENNISSUN.

Boilers for Steam Fire-Eng i nes.

Patented Oct. 19, 1 875.

.Mllmkilllllul Ille aIlfllllllliliIlllllllllrllr/ NFETEHS, PHOTKLLITHOGRAPHER. WASHINGTON. D C.

UNITED STATES PATENT EETGEo JOHN N. DENNI'ssoN, oE NEWARK, NEW JERSEY.

lMPROVEMENT IN BOlLERS FOR STEAM FIRE-ENGINES.

Specification forming part of Letters Patent No. 168,973, dated October 19, 1875; application led December l0, 1674.

To all whom it may concern Be it known that I, JUHN N. DENNISSON, of the city of Newark, State of New Jersey, have invented certain Improvements in the Construct-ion of Boilers for Steam Fire-Engines, of which the following is a specification:

The object of the improvement is expeditin g the generation of steam, by variation in the form of construction, at the first light-ing of the fire under'boilers of steam tire-engines, the alteration decreasing the disproportion of water to heating-surface that occurs in boilers as heretofore constructed.

In the accompanying drawings, Figure 1 is a vertical section of a boiler as improved, dotted lines indicating the form of an ordinary boiler as now constructed. Fig. 2 is a horizontal section of a boiler at the crownsheet of the tire-box.

A is the tire-box; B, the crown-sheet. D indicates smoketubes; E, the upper tubesheet of the smoke-tubes. F shows technically-termed drop-tubes, they being 'suspended from the crown-sheet of the fire-box, their lower ends closed and having water admitted from the upper part of the boiler, at their upper ends, which open'through the crown-sheet from which they are suspended. The inner row of drop-tubes is outside the outer circle of smoke-tubes. rIhe lower part ofthe boiler is ordinarily circular. A square form would admit of an increased number of 1 drop-tubes, which, as there is a greater proportion of heating-surface to the Water than is the case With smoke-tubes, can but be an advantage; but as the same effect would follow an increased size of a circular lower part of the boiler is left to discretion. The dotted lilies show a body of water, Gr, around the outer circle of smoke-tubes, without the same proportion of heating-surface as between the smoke-tubes. In the present construct-ion of steam re-cngine boilers the diameter of the lower part is larger than the upper half,y so as to have one or more rows of droptubes, with the inner roW just outside the inner circumference of the Lipper part of the boiler, with the two diameters joined at or near the water-line inthe boiler, leaving room for a large body of water at the circumference of the upper part of the boiler, between the open tops ot' the droptubes and the water-line in the upper part.

The improvement is shown to contract the space in which the body of water Gr is lodged by bringing the offset down very near to the top ofthe drop-tubes. Heating-surface and water being more equalized, the result is a saving of time in getting up steam when the speedy doing so is an object of much importance.

I do not claim a boiler having an offset, nor do I claim a boiler having drop-tubes, asl am aware that such, when used separately, are

not neW.

What I claim is- The combination, in an upright boiler, baving tubes I), of the offset a land the drop-tubes F, whereby the water is displaced above the drop-tubes, thereby increasing the tire-surface in relation to the quantity of water in the boiler, as set forth.

Y J. N. DENNISSON.

Attest:

W. `M. GooDING, EDWARD CoLLvER. 

